Police recorded the average speed of cars driving on a busy street by a school. for a sample of 36 speeds, it was determined that the average amount over the speed limit for the 36 speeds was 13.2 mph with a standard deviation of 8 mph. the 90% confidence interval estimate for this sample is 10.95 mph to 15.45 mph.
a) what is the margin of error for this problem?
b) what size sample is needed to reduce the margin of error to no more than plus or minus1?

Max recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.